In recent years, portable terminals, such as portable telephones, smartphones, and the like, have come to be used widely. In particular, among portable telephones, foldable-type portable terminals have become more common. Furthermore, foldable-type portable terminals have also been proposed for smartphones. Moreover, covers which are installed on the housing of a portable terminal with the object of protecting the portable terminal have also become common.
Patent Document 1 discloses a foldable-type electronic device including a casing provided with a top cover and a base cover, a display, and a keyboard provided with a plurality of key caps. Patent Document 2 discloses a cover which is suitable for a flat-type portable terminal, such as a smartphone and/or a tablet computer.